The work is related to studies on the structure, function and biosynthesis of gonadotropins. The structural studies include the assignment of disulfide bonds in the alpha and beta subunits of human chorionic gonadotropins (hCG), structures of the carbohydrate units of ovine and bovine luteinizing hormones (o, bLH) and pregnant mare serum gonadotropin (PMSG). All the disulfide bonds in hCG-alpha and hCG-beta have been assigned. The carbohydrate structures of oLH and bLH have been determined. It has been found that the carbohydrate structural pattern in them is quite different from that present in other glycoproteins. The work on the carbohydrate structure of PMSG will be initiated. The structure and function studies have focused primarily on the modification of hCG-beta to obtain a highly specific antigen suitable for producing an hCG specific antibody. Also, these studies have included the determination of the role of carbohydrate in the function of hCG. The removal of carbohydrate from hCG has resulted in the derivatives which are inhibitors of adenyl cyclase and steriodogenesis. The mechanism of action of the derivatives will be tested. The biosynthetic studies have involed the determination of the structure of oligosaccharide-lipid intermediate -a precursor of carbohydrate unit in glycoproteins. Finally, the work on the isolation and characterization of hCG/hLH receptor from rat ovaries is in progress.